Process for desulfurizing hydrocarbons using a mixture of boron trifluoride and an alkane sulfonic acid as reagent



`luly 8, 1952 c. E. JOHNSON ETAL 2,602,770 PROCESS FOR DESULFURIZING- HYDROCARBONS USING A MIXTURE OF BORON TRIFLUORIDE AND AN ALKANE SULFONIC ACID AS REAGENT Filed May 23, 1950 (N Q Q 'o vlr b l' o; z\ u L y o Q (a v V) Q L Q E 'Q q Q "3 Q: o E 0u l., o; & u, Q, uN L fr C lI l l" A n) Q (l) l0 t E?) o) Q n* 47 N N 3 Q l Mik Q 'n N h N ,v

'0 l l\ l; u @u i K 2 9 Vf 3 'n 3 *l L E oo u I a 'Si Q w ma Q o Y( A Il A JNVENTORS.- g Q b Carl E. Johnson i, gf Arf/ur R Lien n L www k Arron/Vey Patented July 8, 1952 UNITED STATES ULFURIZING HYDRO- v MIXTURE oF BORON N ALKANE sULFoNIo PROCESS Foa DES oARoNs USING A TRIFLUORIDE AND A ACID AS REAGENT Y Carl E. Johnson,

Hammond, Ind., as

diana Griiith, and Arthur P. Lien,

signers to Standard Oil Company, Chicago, Ill., a corporation of In- Application May 23, 1950, Serial No. 163,672

12 Claims. 1

This invention relates to a process for refining organic materials containing one or more undesired impurities, such as coloring matter, malodorous materials and sulfur or sulfur compounds. More particularly, this invention is concerned With a process for rening, and especially for desulfurizing, hydrocarbon materials such as Sulfur-containing hydrocarbon oils, e. g. petroleum oil fractions.

One object of the present invention is to provide a process for rening and desulfurizing hydrocarbon materials containing sulfur and/or organic sulfur compounds. Another object of our invention is to provide a process for substantially deodorizing sour or mercaptancontaining hydrocarbon materials. An additional object 1s to provide a process for decolorizing hydrocarbon materials, particularly hydrocarbon oils. Stillr another object of our invention is to provide novel mixtures of chemical compounds characterized by a remarkably specific and selective interaction With Organic sulfur compounds. These and other objects of our invention will become apparent from the ensuing description thereof.

The problems of refining hydrocarbon materials, particularly of decolorizing, deodorizing and desulfurizing said materials, have assumed increasing importance in the petroleum, coal derivatives and synthetic fuels industries. Attempts have heretofore been made to utilize the refining properties of BFa alone and in combination with various complex compounds of BFs vvith oxygenated organic compounds, such as ethers, esters and carboxylic acids, asset forth in U. S. Patent 2,495,851 of Arthur l?. Lien and Bernard L. Evering, issued January 31, 1950. Although free BFs in combination with various oxygenated organic compounds has substantial utility for desulfurizing hydrocarbon oils, both the extent of desulfurization and selectivity of these combination solvents heretofore known has left something to be desired.

Briey, We have made the Surprising discovery that mixtures of BFS and certain organic sulionic acids, particularly certain hydrocarbon sulfonic acids, exhibit a remarkable refining capacity for hydrocarbon materials containing sulfur or organic sulfur compounds and/or coloring impurities and/or odoriferous materials, particularly mercaptans. Especially remarkable is the ability of mixtures oi' BFs and certain hydrocarbon sulfonic acids to combine selectively with organic sulfur compounds contained in` hydrocarbon oils, thereby producing solutions of said sulfur compounds in the BFahydrocarbon sulfonic acid mixtures, which solutions are Substantially insoluble in the resultant reiined hydrocarbon oils at moderate or low temperatures. While the mixtures of BFS and certain hydrocarbon sulfonic acids combine with organic sulfur compounds they do not either substantially dissolve or chemically unite with aromatic hydrocarbons or saturated hydrocarbons contained in hydrocarbon oils.

In one particularly desirable aspect, our invention comprises contacting a hydrocarbon oil which is to be refined with a liquid mixture of BFs and a Sulfonic acid, said mixture being present in an amount sufcient to form a distinct liquid phase upon settling, and thereafter effectin-g stratification of the contacting mixture into a liquid layer comprising predominantly rened hydrocarbon oil and a second, immiscible layer comprising predominantly a solution or chemical combination of BFS, sulfonic acid and impurities derived from the hydrocarbon oil charging stock.

To consider the invention in greater detail, the novel refining agent, as has been indicated generally above, comprises certain organic sulfonic acids. may contain between 1 and 10 carbon atoms, inelusive, in the molecule. We have found hydrocarbon sulfonic acids such as alkanesulfonic acids to be particularly desirable. Although alkanesulfonic acids containing 1 to 10 carbon atoms may be applied for the purposes of our invention, We prefer to employ those acids containing 1 to 5 carbon atoms, inclusive, and more especially 1 to 3 carbon atoms, inclusive, per molecule by reason ofv their lhighly selective combination with the organic sulfur compounds contained in hydrocarbon materials, particularly in petroleum oil fractions. Thus. we may employ, in addition to BFs, alkanesulfonic acids such as methane, ethane. propane, butane, pentane, hexane-sulfonic acids and the like. Particularly, We may employ alkanesulfonic acids prepared by nitrogen oxide-catalyzed air oxidation of alkyl disulfides, e. g., as described in U. IS. Patent 2,433,395 of Wayne A. Proell et al., patented December 30, 1947, the analyses of Vwhich as commercially produced and the properties of which are described by W. A. Proell et al. in a publication in Ind.Eng. Chem. 40, 1129-1132, (June, 1948). It should be, understood, however, that We are not limited to the employment of organic sulfonic acids produced by any particular process. 1

Suitable organic sulfonic acids` ySaturated hydrocarbon sulfonic acids, containing also chloroalkane sulfonic acids or chlorocycloalkanesulfonic acids, can be produced by the so-called Reed Process, which involves treatment of a paraflinic or cycloparaffinic hydrocarbon with mixtures of SO2 and C12 under ultraviolet irradiation to produce saturated hydrocarbon sulfonyl chlorides, which can be converted to the corresponding sulfonic acids. The Reed Process-derived sulfonic acids may be employed for the purposes of our invention.

We may also employ aromatic-substituted alkanesulfonic acids such as benzylsulfonic, alphaphenethylsulfonic. beta-phenethylsulfonic, 3- phenylpropanesulfonic acids, and the like. Aromatic sulfonic acids such as benzenesulfonic, toluenesulfonic, xylylsulfonic, ethylbenzenesulfonic, chlorobenzenesulfonic and cumenesulfonic acids also come within the purview of the present invention.

The sulfonic acids which we employ may contain small proportions, between about 0.1 and about 5 percent by weight, of sufuric acid. The sulfonic acids should be substantially anhydrous for the purposes of the .present invention, i. e., they should not ContainV more than about 8 percent by weight of water.

The molar ratio of sulfonic acid to BFE in the liquid refining mixtures may vary from about l to about 20. Usually vWe prefer to maintain a molar excess of sulfonic acid with relation to BFx, viz., to use more than l but not more than about l0 mols, Vpreferably about 3 to about 8 mols of sulfonic `acid,.such as a Ci-Ca alkanesulfonic acid, per mol of BFS. We have noted that mixtures of BFa and alkanesulfonic acids containing a molar excess of the latter exhibit considerably lower Vapor pressures than mixtures in which free or excess BFz is present.

Although we have referred to mixtures of BFS and hydrocarbon sulfonic acids, there is reason to believe'that actually chemical compounds or complexes can be formed upon absorption of BFS in these acids. For example, measurements of the absorption of BF3 in methanesulfonic acid ,l

at C. indicate the Vformation of the complex compound BFaZCHsSOaI-I. Aromatic sulfonic acids exhibit a decreased tendency to form BB3 complexes in the absence of sulfur compounds such as mercaptans, thioethers, etc., but in the presence of the latter, complexes containing BFs, aromatic sulfonic acid and probably a sulfur compound such as a thioether or the like appear to be readily formed.

The BFa-organic sulfonic treating agent is usually employed in proportions between about 5 and about 200 percent by volume, based on the volume of the hydrocarbon material which is employed as the charging stock. The minimum proportion of the refining agent is determined by the minimum amount required in a specific instance to exceed its solubility in the hydrocarbon material being treated; that is to say, the minimum amount of refining agent should be at least sufficient under the treating conditions to form a distinct liquid phase in a quiescent system. The maximum proportion of refining agent will depend upon the extent 'of rening desired to be effected and, to some extent, by the other conditions of treatment, for example, intimacy of contacting, temperature and time. In refining processes primarily conducted for the desulfurization of hydrocarbon oils, it is desirable to use a sufficient proportion of the combination refining agent to obtain a molar ratio of BFs to the organic sulfur compounds in the oil of at least about 0.5, and preferably one or even more when thoroughgoing desulfurization is desired.

Although certain sulfonic acids which may be employed for the purposes of the present invention are solid or semi-solid materials at room temperature or the desired refining temperatures, We have noted that the addition of BF3 thereto lowers their melting or solidification points and readily permits their use for the purposes of the present invention. Moreover, the absorption of sulfur compounds and other impurities from a hydrocarbon oil by the BFs-organic sulfonic acid refining agent serves further to reduce its softening or solidification point. If desired, a slurry of the organic sulfonic acid in a saturated hydrocarbon diluent may be employed for the purposes of Jthis invention and combined with BFs prior to the refining operation to produce at least partial liquefaction. A slurry of organic sulfonic acid in a saturated hydrocarbon diluent can be contacted simultaneously with the hydrocarbon material to be refined and with BFs.

The present refining process may be conducted at temperatures within the range of about -30 to about C. For reasons of economy, efficiency and convenience, however, we usually prefer to employ temperatures between about 10 C. and about 60 C.

The present refining process is ordinarily conducted under pressure sufficient at least to maintain the BFa-organic sulfonic acid refining agent substantially in the liquid phase, although it should be understood that 4the present process may, if desired, be conducted under such conditions that a substantial partial pressure of BF: exists in the vapor phase of the refining zone. We should like to point out. however, that one of the principal advantages of the present refining agent and process, in comparison with prior art processes which have utilized VBls or BFs in combination With BFa-organic compound complexes, is that the present process can be operated very effectively even at atmospheric pressure, with little or no partial'BFa pressure in the Vapor space of the refining zone. Thus, when at least about 1 mol, preferably at least about 2 mols, of organic sulfonic acid is employed per mol of BFa in the refining agent, the refining agent is characterized by a relatively low partial pressure of free BFa in the vapor phase in equilibrium with the liquid phase, at moderate temperatures. In general, the present process permits the utilization of pressures which are common in the design of commercial process equipment, for example, between about 15 and about 500 p. s. i. g.,al though, more usually, process equipment for use in connection with this invention will be designed for operating pressures inthe range of about 15 to about 100 p. s.'i. g.

The time period required in the present refining process will be dependent, naturally, upon the intimacy of contacting with the refining agent of the hydrocarbon material being treated and upon the operating temperature. Ordinarily, the time period is selected between about 1/2 and about 30 minutes. rI'he operating temperature will, to some extent, affect the intimacy of .contacting by determining the liquid viscosities in the refining system and, probably toa more important extent, by determining the Vrate of interaction of sulfur compounds and other impurities in the feed stock with the refining agent. Although the present process has been referred to as a refining or extraction process, there is reason to believe that the actual mechanism of rening in the present process is a chemical or quasi-chemical union of organic sulfur compounds, colored impurities and the like with the highly acidic, chemically reactive, BFE-organic sulfonic acid refining agent.

The present refining process is applicable to various liquid or liquefied hydrocarbon materials. Thus, it is applicable to various petroleum fractions for the purposes of removing sulfur, gums or other resinous materials, colored impurities and odoriferous compounds, particularly mercaptans. Suitable petroleum feed stocks may comprise light naphtha fractions, gasolines, heavy naphthas, kerosenes, heater oils, furnace oils, diesel fuels, gas oils, cycle stocks from thermal or catalytic cracking operations, reduced crude oils and crude oils. The present refining process can be applied for the purpose of desulfurizing various petroleum stocks which are to be subsequently treated in refining or conversion operations in which sulfur or sulfur compounds are undesirable, for example, catalytic cracking operations, catalytic reforming operations, catalytic hydroforming operations, catalytic hydrogenationin the presence of sulfur-sensitive catalysts and the like.

We have noted that the BF'a-hydrocarbon sulfonic acid refining agents exert a remarkable specificity in their interaction with organic sulfur compounds to the exclusion of complex formation with both low boiling and high boiling aromatic hydrocarbons, examples of the former being m-xylene or mixtures of mand p-xylene and an example of the latter being the high boiling aromatic hydrocarbons contained in gas oils. The selectivity of interaction of the BFs-hydrocarbon sulfonic acid rening agents to the exclusion of reaction with aromatic hydrocarbons is even greater than that of an active silica gel. So far as we are aware, the BFa-hydrocarbon sulfonic acid rening agents have the highest sulfur selectivity of any treating reagent, including even liquid hydrogen uoride which had the highestrsulfur selectivity factor of any treating reagent known to us. It will be apparent, accordingly, that the BFa-sulfonic acid refining agents may be applied to the desulfurization of aromatic hydrocarbon fractions, for example, sulfur-containing leenzol, toluol, xylol or naphthalene fractions, or the like.

The present process may also be applied to the refining of various coal tar fractions and coal tar distillates. In the rening of shale oil fractions the present refining agents serve not only to remove organic sulfur compounds. from the feed stock, but also to remove oxygen compounds and nitrogen compounds. It should be understood that the above specific examples of charging stocks which may be refined in accordance with the present invention are illustrative only and are not intended to limit the field of applicability of the process of the present invention.

When substantial proportions of oleiins are contained in the charging stock and it is not desired to remove them from said stock, it is desirable to carry out the refining operations in the presence of cognate or added alkylatable hydrocarbons, for example, isoparans such as isobutane, isopentaneor the like; cycloalkanes containing a tertiary hydrogen, for example, methylcyclopentane, methylcyclohexane, ethylcyclohexane, and the like; varomatic hydrocarbons such yas benzene; toluene, xylenes, ethylbenzene, naphthalene or'the like.

6. The presentprocessr canbe carried out in batch, continuous'or semi-continuous operating cycles, employing contacting and separation equipment such as has heretofore been' employed in the selective solvent refining of petroleum lubricating oil stocks or in effecting the alkylation of isoparafnic hydrocarbons with olefins in the presence of liquid acid catalysts. It should be understood `that the specific equipment einployed forms no part of the present invention and that any equipment adaptable for the purposes of contacting the BFa-organic sulfonic acid refining agent with the hydrocarbon charging stock and thereafter separating spent refining agent from the refined charging stock can be employed for the purposes of the invention.

In order more fully to describe one specic embodiment of our invention, reference is made to the annexed figure. The feed stock, for example, a sulfur-bearing hydrocarbon material such as a straight run heater oil derived from distillation of ya West Texas crude oil, is passed through valved line I0 into a drying zone Il, wherein it is substantially dehydrated, thence through line I2 into the refining equipment, which in the ligure is depicted as an extraction tower I3. Drying zone II may comprise conventional drying reagents and equipment and may, for example, take the form of a vessel packed with excelsior, fiber glass, a commercial mag# nesium silicate drying agentiFlorisl), alumina gel or `the like. If desired, the viscosity of the hydrocarbon feed stock can be reduced by dilution with a saturated hydrocarbon diluent such as n-pentane, isopentane, n-octane, petroleum ether, methylcyclopentane, cyclohexane or the like, which may be introduced into line I2 through valved line I4.

Extraction tower I3 may, if desired, be packed with suitable corrosion-resistant packing material, for example, structural carbon in the form of Berl saddles, glass or porcelain spheres, Monel metal fragments, mild carbon steel jack chain or the like, or may be provided with mechanicallyor magnetically-actuated agitators. The extraction or chemical combination of sulfur compounds with the refining agent is slightly exothermic. Accordingly, it may be desirable to provide a cooling coil, cooling jacket or other means of heat removal in the extraction zone. A cooling jacket I5 is depicted in the figure. When a low boiling hydrocarbon diluent such as npentane is employed, at least partial heat removal from the extraction zone can be effected by the evaporation of the diluent.

The hydrocarbon sulfonic acid, e. g., a mixture of Ci-Cs alkanesulfonic acids, is introduced into tower I3 through valved line I6. Boron trifluoride is passed through valved line I1 into a manifold I8, whence all or a portion thereof may be passed into line I6, or into line I2 to join the hydrocarbon feed stock. The proportion of combined treating reagent to the hydrocarbon oil may be, for example, about 30 to about 50 volume percent, based on the hydrocarbon oil, and the treating reagent may contain between about 2 and :about 5 mols of the sulfonic acid per mol of.BF3.

Contacting in tower I3 may, for example, be effected at about 20 to about 30 C. at pressures between about l5 and about 50 p. s. i. g. Tower I3 may be operated raffinate-rich or extractrich, but we prefer the latter mode of operation. Meniscus I9 is shown in the ligure as the separation boundary between a lower liquid extract 7 phase. and a. supernatant-liquid ramnate phase comprising predominantly refined hydrocarbon stock. .The contactingperiod in tower I3 can be varied 'between aboutl/2 andi about .30.minutes and may be. for example, about 5 minutes.

Rafnate is rwithdrawn from. tower I'3-Y through line 20. into aseparating vessel. 2.I provided with a Weir 22. Occluded rening agent or extract separates in .the lower portion of vessel 2.1 whence it is withdrawn through valved line. 23. and can be recycled through` valved` line 24.k intov tower I3 below the meniscus or interfacerv I9. Optionally, all or part of the material in line 23 may be passed through valved. line. 25 to be treated with extract derived from the lower portion of tower I3. Any gases which separate in drum 2|' can be vented through valved line 26 into manifold21 for. recycle. to tower I3 or for passage to an absorber, the operation of which will.. be described'hereinafter.

Hydrocarbon raiinate collects in the upper portion of drum 2lV in advance of weir 22 and is discharged through line 28, and pressure reducing valve 2Sthrough line 30 into the upper portion of a stripping tower 3I, which is provided with a reboiler coil 32 and suitable contacting or packing material. Any BF3 which may. have been occluded with the raffinate is vaporized and passes overhead of stripper 3| through line 33 into line 21. If desired, all or part of the rainnate passing through line may be diverted therefrom through valvedline 34 .and either removed from thetreating system or subjected to such further treatments as desired, for example, washing with caustic alkalies or the like. Stripped raffinate is withdrawn. from tower 3I through valved line 35.

A liquid extract layer comprisingpredominantly the BFS-hydrocarbon sulfonic acidrening agent containing sulfurous and. other impurities derived from the hydrocarbon charging stock, is withdrawn from` tower I3` through line 36 and may be treated. by alternative, but. not necessarily mutually exclusive, processing methods which will be described hereinafter.

If desired. allor part of the extractmaterials may be divertedfrom line 36 through pressure reducing valve 31 and line 38intoy strippingv tower 36. which may be provdedwith suitable'packing material and` a..reboiler coil 40. Stripping gases such as flue gases, nitrogen, methane, ethane, propane. natural `gasair or the like may be introduced into the lower portion of tower 39 through valved line 4I .to aid in the stripping 0peratons. Temperatures 'between about 50 and about 250 C. and pressures between about 5 and about 50 p. s. i. a. can be maintained in tower 33 to effect decomposition of the various complex compounds containing BFa which may be present in the extract materials, thereby liberating BFacontaining gases which pass overhead through` line 42 into manifold 21. More or less hydrogen sulde may also be generatedby decomposition of sulfur compoundsat the temperatures attained in theoperation of stripping tower 39, thereby contamina-tingr the BF-.gas stream pass-.- ing overhead throughline 42.

The stripped extract materials are withdrawn from the lowerl portion of tower 39 through valved line 43,intosettling drum44. As a result of substantial Orcomplete removal of Blb from the extract layer, thefextractslayer canbe .separated by sett1ing, centrifuging or 'the'like into Aone liquid layer; comprisingpredom-inantly hydrocarbon sulfonicacidand al second liquid-1ayercom prising predominantly sulfur. compounds and/or other impurities derived from the hydrocarbon charging stock. The impurities are withdrawn through valved line 45. The sulfonic acid may be withdrawn from the lower portion of drum 44 through line 66, thence through valved line 41 for recycle to line I6and refining tower I3. Optionally, part or all of the sulfonic acid may be diverted from line 4.6 through valved line 48 and heater 4S into avacuum. still 50, provided with residue draw-off line 5I and distillate draw-off line 52. Depending` upon the boiling points. of the residual contaminants which may be present in the sulfonic acid and the boiling point of the sulfonic acid, one or the other may be separated as a distillate and the other as a residue. The vacuum distillation treatment improves the quality of the sulfonic acid and fits it for further recycle (by lines not shown) to reiining tower I3.

An optional treatment for sulfonic acid containing residual contaminants and. in fact, a treatment to which the entire extract phase may be subjected if desired, involves dilution with water to separate contaminant materials derived from the hydrocarbon charging stock. In this mode of operation, the sulfonic acid is diverted from line 45 through valved line 53 into line 54. whence it is joined by water, for example, in proportions between about 10 and about 200 volume percent, introduced through valved line 55. If desired, part or all of the extract layer may be diverted from line 36 into valved line 54. The resultantaqueous mixture may be passed through heat exchanger 56 into settling drum 51 provided with Weir 58. In'drum 51, gravity separation is effected between extract materials, i. e., sulfur compounds and other contaminants `derived from the hydrocarbon feedstock and an aqueous solution of the components of the refining agent. Extract materials may be removed from drum 51 through valved line 59.and the aqueous refining agent may be removed from drum 51 through valved lineLiilv into concentration or recovery equipment schematically depicted at 6I, employing conventionalmethodsand equipment, thence through valved line 62. into line 41 for recycle through valvedv line IE to rening tower I3.

Manifold 21 contains gases comprising BFJ, relatively low boiling saturated hydrocarbons employed as a diluent in refining tower I 3 and/or as stripping gases introduced through tower 39, together with more or less hydrogen sulfide clerived from 'decomposition of organic sulfur compounds in tower 39. Part or all of the stream in manifold 21. may be passed through valve 63 and heat exchanger 6'4into line I61for recycle to rening tower I3. Preferably, part or all of the gas stream in manifold 21 is passed through valve65 into an absorption tower 66; there to be countercurrently contacted with liquidhydrocarbon sulfonic acid, introduced through valved line 61, which selectively absorbs and complexes the BFs component of the gas stream to produce a solution which iswithdrawn through valved line 68 and can suitably berecycled (by lines not shown) to refining tower I 3. Unabsorbed diluent gases pass overhead from absorber 66 through valved line 69. In order to'increasethe extent and eiliciency of BFS recovery it may be desirable to charge sulfur compounds, particularly alkyl thioethers or a portion ofthe sulfur-containing hydrocarbon feedstock.. into the upper portion of tower 66, preferably through line 61.

The following specic examples areintended to be iuustretive but not nduiynimitetiveef the present invention.

Example '1 Y The charging stock was a West Texas heater oil having a sour odor, orange-yellow color, 332 to 548 F. A. S. T. M. boiling range, sulfur content of 0.78 weight percent and 48 mercaptan number. The oil (151.ml.) was contacted with 23.5 percent by volume of Y a BFa-methanesulfonic acid liquid mixture containing 0.488 mol of methanesulfonic acid and 0.1075 mol BFa at room temperature (20-25 C.) and atmospheric pressure by shaking forf minutes in a glass vessel. Upon cessation of shaking, the contents of the vessel separated into a supernatant liquid ranate phase and a lower extract phase comprising the BFs-methaucsulfonic acid refining agent. percent by Volume of the initial heater =oil chareing stock and contained 0.29 weight percent sulfur, indicating that 62.9.'percent desulfurization occurred. The rafinate layerlwas separated from the extract and washed with water. The rainate thus treated had a very light yellow color, a sweet odor and a mercaptan number of 16. The mercaptan number is the.. number of milligrams of mercaptan sulfur per 100 ml. of sample. 'The extract layer was diluted with water, whereupon it separated into an aqueous phase comprising the refining agents and a supernatant layer of 5 ml. (3.3 volume percent of feed) of a dark brown, foul-smelling oil which contained 12.4 percent by weight of sulfur. Therefore, the sulfur selectivity factor of the rening agent j i .desulfurization X extract in the above-described operation was 190.

By way of comparison; the treatment of a West Texas furnace oil (1.46 percent sulfur; 438-632 F. A. S. T; boiling range) with 34 g. BFs per 640 g. of oil at room temperature and p. s. i. g. resulted in only 17.8 percent desulfurization. These results are' 'in'sharp contrast to the above example. The proportion of BFS based on feed in the above example was 5.6 weight percent whereas it was 5.3 weight percent based on feed in the instance in which methanesulfonic acid was not'employed. The desulfurization data are, therefore, reasonably comparable. i

Attention is likewise drawn to'Example 4,

Table 1 of U. S. Patent 2,495,851 wherein treatr` ment of West Texas furnace oil (1.46 percent sulfur) with 20 volume percent of BFs-ethyl Vether complex resulted' inV only' 9.9 percent desulfurization. It will, thus, be apparent that whereas free BFs is essential totactivate the BF2. complexes described in U. S. `Patent 2,495,851, no free BFa is essentialin the present process, since, as shown by the above example, V4.35 mols of methanesulfonic acid were presentfor each mol of BFS employed. Y

To compare the action of asulfonic acid alone, 10 ml. of a West Texas heater oil, containing 0.78 weight percent 'of sulfur, were contacted with 4 ml. of mixed Ci-C4 alkanesulfonicv acids by stirring for minutes at'rom temperature. The mixture was then `allowed to stratify into an The. ranate phase amounted to 96.7

upper, hydrocarbonlayer'and a lower, acid layer, i

and the layers were separated. The hydrocarbon layer was washed with 10 ml.- of water, then in 10;rvnl .,waterand nally with 10V-1111.503? distilled water. The ,treated hydrocarbon layer contained 0.77 weight percent of sulfur, indicati# ing that essentially no desulfurization occurred.

In order to compare the BFa-sulfonic acid refining agents ofthe presentjinvention withBFa.- carboxylic acid rening agents, aheater o ilc'onL- taining 0.73' percent by weight lof sulfurwas treated withi BF352CH3CO'2H in the proportion' of 57 ml. of complex" per 182 Iml.' of heater' oil at atmospheric pressure, 20 toi25"A C. and 5 minutes of contact. Only 8 percentfdesulfurization'fof the feed was thus obtained.'

f Example f2 The West Texas heater"foil Afof Example 1 (0.78 percent sulfur)V was contacted 4'at atrfls pheric pressure and'O to 5 C. with 31.3`V'olun`1e percent of a BFaf-methanesulfonic acid liquid mixtureA by occasional shaking overa'30 minute period. The refining agent `contained0.7 82 `mol of methanesulfonicn acid anidl0-214 molofBFs and was used tojtreat *1 82 ml. of feed. Thecon.- tactin'g mixture' was then allowedto settle, forniing a two-liquid`layer system. The upper, rafiinate hydrocarbon 4layer wasaseparated. .and Washed with water; .it Vwas. found toI constitute 96.2 percent by voluncof the `heateroil charging stock `and toA contain 0.16 percent sulfur. The refractive index '(nDZ) of thefe'edfwas 1.4602 and of the rainate, 1.45821' The .extract v`mate-- rial was characterized .by vva sulfurpontent of 11.9 percent and refractive index'.of-"1.509'0. Since 79.5 percentV desulfurization ofthefeed had occurred .with a' 3.8 volume percent loss of -oil on extraction, the Vsulfur selectivity .factor in this operation was 21,5. i

` Example' 3 A west .Texas gas ou (A. s. T. M. `toning range, 4321-650"` F.;V sulfur content of ..1.50'weig'ht percent; n.320 of 1.4825) was extracted at room temperature and atmospheric pressure with v31.2.perlcent by volume of a BEb-.methanesulfonic acid liquid mixture'containing44 mols o f methanesulfonic acid per mol of BFs. andthe mixture worked up Yas described .inprevious examples.

As a result, .51.3 percent. desulfurization was obtained at-an extract .volume equal to 9.1 volume percent of the feed stock.- Accordingly, the sulf Vfur selectivity factor inthis operation was 56.4.

Y y ""Erdmpze'r. y p The gas oil charging stockl ofsExamplevB was extracted bythe same procedure-with 30 volume and atmospheric'pressure. Ranate and extract phases were separated and worked up asin previous examples; The refining treatment produced less than 2 Volume percent of extract, based on the naphtha 'chargedand the raffinate vwas found to contain only 0.07 percent of sulfur,

with a solution 'oflml of concentrated ammonia 75 corresponding to -78"percent desulfurization Iof 11 the naphtha. The sulfur selectivity -factor in this operation, `accordingly, was somewhat over l400.

Example 6 A mixture of 160 ml. of toluene and 20 m1. of thiophene was contactedwith 46v ml. of the BFamethanesulfonic acid refining agent described in Example 5. As a result, appreciable quantities of heat were evolved, the contacting mixture darkened and viscous resinous materials were produced. A supernatant rafiinate layer was formed on settling the.,contacting mixture and was separated. The raflinate contained 2.41 percent by weight of sulfur, while the charging stock analyzed 4.48 percent;` by weight of sulfur. As a result of thentreatment, 46.2 percent .desulfurization of the charging stock occurred.

Example 7 A West Texas heater oil containing 0.73 weight percent of sulfur (152 ml.) was mixed with commercial p-toluenesulfonic acid and BFs was bubbledv through the resultant mixture .at room temperature. The volume ratio of extractant to oil was 0.30 and the extraction mixture contained 0.346 mol of sulfonio acid and 0.0826 mol of BFS. Upon standing, the .extraction mixture separated into an upper, hydrocarbon layer and a lower, acid layer. Thev hydrocarbon layer (rainate) was found to contain 0.44 weight percent of sulfur, indicating'that the Vextraction treatment had resulted in `43.6 weight percent desulfurization of the heater oil. The extract was estimated as 3 percent by volume, based on feed. The sulfur selectivity factor was therefore about 145 in this operation.

An overall comparison 4of the above examples indicates that the sulfur selectivity factors tend to decrease somewhat with increasing average molecular weight or boiling range of the hydrocarbon charging stock subjected to the refining process of the present invention.

The extracts produced in the process of the present invention are in themselves useful compositions of matter. Thus, they may be caused to react with olefinic or terpenic compounds to produce derivatives of the sulfur compounds therein contained. Treatment with olefins may be employed to convert mercaptans in .the extracts to thioethers. Moreover, condensation reactions may be effected in the extract and hydrogen sulfide evolved by subjecting the extracts to elevated temperatures. If desired, the extract sulfonic acid mixture in an amount sufiicientat least to form a separate liquid phase at a temperature between about 30 C. and about 120 C., and separating a refined hydrocarbon material and an extract phase comprising BFs, hydrocarbon sulfonic-acid and a sulfur compound. v

3. The process of claim 2 in which said contacting is effected at aftemperature between about 10 C. and about 60 C. l

4. The method of desulfurizing a sulfur-bearing hydrocarbon vmaterial which comprises contacting said material withfbetween about 5 and about 200 percent by volume of a liquid mixture of `BF3 and a hydrocarbon sulfonic acid containing 1 to 10 carbon atoms,vin`clusive, per molecule, at a temperature between about 30 C.4 and about 120-C., and separating a refinedhydrocarbon material and van extract phase comprising BFS, hydrocarbon sulfonic acid and a sulfur compound. f.

5. The process of claim4 inV which the'proportion of the liquid'BF-hydrocarbon sulfonic acid.

' based on said hydrocarbon material, is between about 20v percent and ume,

6. The process of claim 4 in which the proportion of the liquid BFa-hydrocarbon sulfonic acid, based on said hydrocarbon material, is between about 20 percent and about 100 percent by volume, and infwhich said contacting 'is eiected at a temperature between about 10 C. and about 60 C.

7. 'I'he method of desulfurizing a sulfur-bearing hydrocarbon materiall which comprises conabout 100 percent by voltacting said material with between about 5 and comprises contacting said hydrocarbon oil with materials may be treated to recover substantially A prure sulfur compounds, Vemploying the water dilution method described in connection with the annexed figure, optionally followed by Vvacuum distillation of the `sulfur compounds thus liberated.

It will be apparent that the refining process of the present invention can be employed in combination with other refining processes.

Having thus described our invention, what we claim is:

1. The method of desulfurizing a sulfur-bearing hydrocarbon material which comprises contacting said material with a Blas-hydrocarbon sulfonic acid mixture in an amount suflicient at least'to form a separate liquid phase, and sepn arating a refined hydrocarbon material and an extract phase comprising .BFs, hydrocarbon sulfonic acid and a sulfur compound.

2. The method of desulfurizing a sulfur-bearing hydrocarbon material which comprises contacting said material with a EPs-hydrocarbon about 200 percent by volume of a liquid mixture cf BFa and an alkanesulfonic acid containing 1 to 3 carbon atoms, inclusive, per molecule, at a temperature between aboutA 30 C. and about C., and separating a rened hydrocarbon material and an extract' phase comprising BFQ, alkanesulfonic acid and asulfur compound.

8. The method of removing mercaptans from a mercaptan-containing hydrocarbon oil which between about 5 and .about 200 percent by volume of a vliquidinixture of BFs and an alkanesulfonic acid containing 1 to 3 carbon atoms, inclusive, per molecule at a temperature between about 30 C. and about'120" C., and separating the contacting mixture Yinto an extract layer and a refined hydrocarbon oil layer containing a substantially reduced Vquantity ofmercaptans.

9. The methodof'desulfurizing a sulfur-bearing hydrocarbon material which comprises contacting said material with a liquid mixture comprising BF; and a vhydrocarbon Asulfonic acid in substantial molar excess, based on the amount of B115, the amount ofsaid liquid being sufiicient at least to form a distinct liquid phase, and separating a refined hydrocarbon material and an extract phase comprising BF3, hydrocarbon sulfonic acid and a sulfur compound.

10. The process of claim 9 wherein said liquid mixture contains from about 3 to about 8 mols of hydrocarbon sulfonic'acid per mol of BFa.

11. The method of desulfurizing a sulfur-bearing hydrocarbon material whichv comprises contacting said material with between about 5 and about 200 percent by` volume of a liquid mixture comprising essentially BFa and an alkanesulfonic acid containing 1 to 3 carbon atoms, inclusive, per molecule, the molar ratio of said alkanesulfonic acid to said BFs in said liquid mixture being 13 between about 3 and about 8, at a temperature between about 30 C. and about 120 C., and separating a rened hydrocarbon material and an extract phase comprising BFa, said alkanesulfonic acid and a sulfur compound. n

12. The process of claim 11 wherein the a1- kanesulfonic acid is methanesulfonc acid and wherein said contacting is eiected at a temperature between about 10 C. and about 60 C.

CARL E. JOHNSON. ARTHUR P. LIEN.

REFERENCES CITED The following references are of record in the le of this patent:

Number Number 14 UNITED STATES PATENTS Name Date Moser Sept. 22, 1936 Burk Mar. '7, 1944 Horeczy Feb. 4, 1947 FOREIGN PATENTS Country Date Great Britain May 23, 1929 Great Britain Sept. 1, 1939 Great Britain Sept. 1, 1939 

1. THE METHOD OF DESULFURIZING A SULFUR-BEARING HYDROCARBON MATERIAL WHICH COMPRISES CONTACTING SAID MATERIAL WITH A BF3-HYDROCARBON SULFONIC ACID MIXTURE IN AN AMOUNT SUFFICIENT AT LEAST TO FORM A SEPARATE LIQUID PHASE, AND SEPARATING A REFINED HYDROCARBON MATERIAL AND AN EXTRACT PHASE COMPRISING BF3, HYDROCARBON SULFONIC ACID AND A SULFUR COMPOUND. 